Chemistry of di- and tri-metal complexes with bridging carbene or carbyne ligands. Part 23. Alkyne insertion into heteronuclear dimetal compounds with bridging tolylmethylidyne ligands; crystal structures of [FeW{µ-C(C₆H₄Me-4)C(Me)C(Me)}(CO)₅(η-C₅H₅)] and [Fe₂W(µ₃-CC₆H₄Me-4)(µ-Me₃SiC₂SiMe₃)(µ-CO)(CO)₆(η-C₅H₅)]

Abstract

BS8 I TSCobalt-tungsten complexes [CoW(p-CRCRtCR2) (C0)2(q-C5H5) (q-C5Me5)] (R = C6H4Me-4 ; R1 = R2 = Ph or Me; R1 = Ph or Me, R2 = M e or Ph; R1 = But, R2 = H), with ally1 groups bridging the Co-W bonds, have been prepared by heating the alkynes PhCECPh, MeC-CMe, MeCGCPh, and Bu'C-CH with the compound [CoW(p-CR)(C0),(q-C5H5) (q-C5Me5)]. Related iron-tungsten compounds [FeW(p-CRCR1CR2)(C0)5(q-C5H5)] (R1 = R2 = Me, Ph, C6H4Me-4, or CF3) have been prepared by heating the appropriate alkyne R1 C=CR2 with the cluster complex [Fe2W(p3-CR)-(p-CO) (CO)a(q-C5H5)] in toluene. In contrast, the diiron-tungsten species reacts with Me3SiC=CSiMe3 and with Bu1C=CSiMe3 to afford compounds [Fe2W(p3-CR) (p-alkyne) (p-CO) (C0)6(q-C5H5)] which retain the p3-CFe2W structural core, the product from Bu1C=CSiMe3 being formed as a mixture of isomers. The H and ?3C-(l H} n.m.r. data for all the compounds are reported and discussed, and the molecular structures of [ FeW(p-C( C6H4Me-4) C( Me) C( Me) )( CO) 5(q-C5H5)] and [ Fe2W(p3-CC6H4Me-4) (p-Me3SiC2SiMe3) (p-CO) (CO)6(q-C5H5)] have been established by X-ray diffraction. In the dimetal compound the Fe-W bond [2.720(1) A] is bridged by a three-carbon chain [mean C-C 1.438(8) A]. Whereas all the atoms of the chain are bound to the iron [2.047(6), 2.1 03(6), and 2.083(6) A], only the t w o end carbons are attached to the tungsten [2.194(6) and 2.164(7) A]. The iron * 1 ,I ,I ,2,2-Pentacarbonyl-2-q-cyclopentadienyl-~.~-[ 1',2'-dimethyl-3'-ptolylpropen-1 '-~1-3'-ylidene-C*-~( Fe)C*.3(W)]-irontungsten (Fe-W ) and 1,3-~.~-bis(trirnethylsilyi)acetylene-1,2-p-carbonyl-I , I ,2,2,2,3-hexacarbonyI-3-q-cyclopentadienyl-~~-~-tolylmethy~idyne-triangulo-di-irontungsten.compound from which they are prepared. In this event two different reaction pathways may be followed; both, however, involve C-C bond formation. Either dimerisation of the tolylmethylidynetungsten complex occurs to give [ W2(p-RC2R)-(CO)4(q-CsHs)2], or more usefully trimetal clusters are produced with MW2 triangles bridged by the alkyne C2(C,H,Me-4)2.5*9.10 The chemistry of carbyne groups when bridging metal-metal bonds is currently of interest, and this prompted us to study reactions of alkynes with some of the di-and trimetal compounds containing p-CR ligands. It was expected that C-C bond-forming processes would be observed, as found with some of the reactions of [W(XR)(CO),(q-C,H,)] mentioned above. In this paper we describe reactions of the species [CoW(~-CR)(CO),(q-CsHs)(q-C,Me,)] and [Fe2W-(p3-CR)(p-CO)(C0),(q-C5Hs)] with alkynes. A preliminary report has been given." Results and DiscussionThe compound [CoW(p-CR)(CO),(q-C5Hs)(q-CsMe,)] proved to be relatively inert towards alkynes, and no significant reaction occurred unless the reactants were heated in toluene

Chemistry of polynuclear metal complexes with bridging carbene or carbyne ligands. Part 77. Reactions of iron–molybdenum compounds with alkynes; crystal structures of [MoFe{µ-C(C6H4Me-4)C(CHMe)CH2C(Me)C(Me)}(CO)4(η-C5H5)], [MoFe{µ-C(C6H4Me-4)C(CHMe)CH2}(CO)5(η-C5H5)], and [MoFe{µ-C(C6H4Me-4)C(CH2PMe3)CHMe}(CO)5(η-C5Garcı́a1, Jeffery2, Sherwood3 et al. 1988J. Chem. Soc., Dalton Trans.Self Cite13130View full textAdd to dashboardCite

“…The Mo-Fe separation in (4) lies between those found in the complexes (la) [2.823( 1) A] and [MoFe(p-q2-SCC,H,Me-4)-( C0),(q-C5H5)] [2.765( 1) A]." These distances may be assumed to correspond to single bonds since each metal centre has a closed 18 electron shell, based on the electron contributions from the ligating groups.…”

Formation of complexes with C ⋯ H ⋯ Mn interactions from reactions of dienes or acetylene with a µ-hydrido heterometallic dimer; X-ray crystal structures of [(η5-C5H5)MoMn(µ-H)(µ-PPh2)(CO)6], [(η5-C5H5)MoMn{µ–σ : η3-CH2C(Me)CHMe}(µ-PPh2)(CO)4], and [(η5-C5H5)MoMn{µ–σ : η4-CHCHCH2CHPPh2}(CO)4]

“…. Bond lengths: Mn(1)-Mo(l), 3.088 (1); Mn(1)-P(l), C ( 12), 1.954 (7); Mn( 1)-C(21), 1.842 (6); Mn( 1)-C(22), 1.820 (6); Mn( l)-C(23), 1.853 (6); Mn( 1)-C(24), 1.81 l(5); Mo( 1)-C( Cp, av.) , 2.34(2) A.…”

“…40% yield. Complex (1) has been 2.294 (2); Mo( 1)-P( l), 2.435 ( 1); Mo( 1)-C( 1 l), 1.950 (6); Mo( 1)t Selected spectroscopic data [i.r. (vco cm-1) measured in hexane solution; 1H and I3C n.m.r.…”

Chemistry of di- and tri-metal complexes with bridging carbene or carbyne ligands. Part 29. Synthesis of rhenium–tungsten compounds; X-ray crystal structures of [ReW2(µ-Br)(µ-L)(µ-CC6H4Me-4)(µ3-CC6H4Me-4)(CO)3(η-C5H5)2](L = CO or O)

“…Re-C(9) 2.017 (19) Re-C(8) 1.933 ( 19) R e 0 2.515(3) C( 7)-O(7) 2.1 14( 18) C( 9)-0(9) 2.071( 18 1 09.5 ( 8) Re-Br-W( If the reaction between [ Re2(p-Br)2(thf)2(C0)6] and [W(=CR)(CO),(q-C,H,)] is carried out using an excess of the latter reagent in addition to (2) another complex (3) is produced, albeit in low yield. Experiments established that (3) is not formed by treating (2) with [W(rCR)(C0)2(q-CsHs)].…”

“…Although, this signal is less deshielded than those for the p3-C nuclei in compounds ( 1)-( 4), it is similar to that observed (257.7 p.p.m.) for the triply bridging carbon in [Fe2W(p3-CR)(p-Me3SiC2SiMe3)- 19 This di-irontungsten compound has a structure with the alkyne edge-bridging and is thus related to (S), which also has a trimetallatetrahedrane core but with the SCR group edge-bridging. The relative shielding of the p3-C resonance in (5) may be due to incipient interaction with the ligated carbon of the SCR group, to which we assign the signal at 6 90.9 p.p.m.…”